Detection of Potassium Ion via Silicon Nanowire Field-Effect Transistor
Date Issued
2009
Date
2009
Author(s)
Sun, Chih-Jung
Abstract
In the past decades, silicon nanowires （SiNWs） have been intensively studied, because they are excellent candidates for a variety of applications. In particular, SiNWs-based field-effect transistor （SiNW-FET） can be used as chemical and/or biological sensors taking advantages of their ultrasensitivity, real-time response, and label-free detection. In the sensing applications, SiNW-FET has been employed as ion-selective field-effect transistor （ISFET）, where a selective ionophore was modified on the surface of the SiNW-FET to detect a specific ion. The conductance change inside the ionophore-modified SiNW-FET depends on the electric field exerted from the ion-ionophore complex, which plays the role of a ionic gate to the FET-based device. Because of the considerably large binding constant between valinomycin and potassium ion （K+）, valinomycin-modified SiNW-FET was fabricated in this study to detect K+ in aqueous solution. The binding constant between valinomycin and K+ is determined from a model fitting to the measured curve of conductance change versus K+ concentration. This valinomycin-modified SiNW-FET is suitable for quantitative analysis and will be applied to monitor the extracellular ionic fluctuation in the future.
Subjects
single crystalline silicon nanowire
field-effect transistor
valinomycin
binding constant
selectivity coefficient
Type
thesis
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